Which description best fits lichen planus?

• A. Neurodermatitis
• B. Polygonal, flat-topped pink papules with Wickham's striae
• C. Fungal scalp infection
• D. Koebner phenomenon only

Answer: (B)

Lichen planus presents with itchy, polygonal, flat-topped papules that are pink to purple in color, and a hallmark feature is Wickham's striae—the fine white lines seen on the surface of the papules or on mucosal areas. This combination of polygonal shape, flat-topped surface, and the characteristic lacy white markings is what makes the description fit best. While the Koebner phenomenon can occur with lichen planus, it is not the defining descriptor of the condition. Neurodermatitis describes thickened plaques from chronic scratching rather than the classic polygonal papules with Wickham's striae, and a fungal scalp infection presents with scaling and hair involvement rather than these distinctive papules with white striae.